Process for the production of alicyclic



assignors to Inventa A.-G.,fiir Forschung und Patentverwertung Luzern, Lucerne, Switzerland.

No Drawing. Filed May s, 1958, Set. No. 733,850 Claims priority, application'switzerland Apr. 9, 1954 1 Claim. (Cl. 260-566) This invention relates to the production of alicyclic ketoximes by catalytic oxydation of hydroxylamines with oxygen containing gases under increased pressure.

This application is a continuation-in-part of our copending application Ser. No. 497,824, filed March 29,

1955, and now abandoned.

Cycloalkylhydroxylamines form valuable intermediate products for the production of synthetic substances. They are usually obtained by reduction of the nitrocycloalkanes. The reduction can be effected for example by catalytic hydrogenation ior electrolytically.

The processes hertofore known for the production of ketoximes from nitrocycloalkanes by direct reduction have the drawback that large quantities of chemicals have to be used. Difliculties are entailed with direct processes for catalytic hydrogenation of nitrocycloalkanes to a great extent, because of the conditions of reaction to be chosen.

Through ;a new oxidation method, it is possible to convert the cycloalkylhydroxylamines with excellent yield into the corresponding alicyclic ketoximes, which can according to the known processes of the Beckmann rearrangement, be converted into the corresponding lactams of the omega-aminocarbonic acids.

According to the present new process, these mentioned drawbacks in the production of ketoximes are obviated, if the cycloalkylhydroxylamines produced at first according to known manner are oxidized with good yield into ketoximes in the presence of metallic salts as catalysts. For oxidizing agent, gases containing oxygen, as for example air, can be used. These gases are used under superatm'ospheric pressure.

Organic salts of copper and cobalt are particularly suitable as catalysts and also suitable are the salts of other metals, such for example as manganese, lead and vanadium. Particularly advantageous are mixed catalysts of the organic salts of the metals of the first and eighth group of the periodic system with salts of only less suitable metals, which produce an activating elfect, in which case the yield as against the experiments in the presence of simple metallic salts is better. Suitable organic acids of these salts, are the organic acids used for linseed oil hardening, such as oleic acids, naphthenic acids, etc. It is possible too, to use soluble metal-salts of other aliphatic or cycloaliphatic monocarbonic acids. The quantity of catalyst is so measured that a maximum in action is attained. This is the case in the use of about 0.1-5% by weight of the metal-ions, related to the quantity of. cycloalkylhydroxylamine to be oxidized. Preferably the hydroxylamines are oxidized in solvents that are stable under the conditions of reaction and at least dissolve the catalyst completely. For solvents, use is made advisably for example of low monovalent alcohols, aliphatic, cycloaliphatic or aromatic hydrocarbons. The solvents are preferably chosen from the group consisting of methanol, ethanol, propanol, cyclohexane and ben- Uni s Sta age 2,947,783 C6 Patented Aug. 2, 1960 zene. The cycloalkylhydroxylamine can be dissolved in the solvent,'but the oxidation can nevertheless be carried out also if the cycloalkylhydroxylamines are present partly as suspension. The oxidation for example of cyclohexylhydroxylamine is accomplished through the arrangement whereby in the mixture of it with the solvent and the catalyst, gases containing oxygen, especially air, are allowed to flow through in finely divided form with maintenance of not too high a reactiontemperature. The temperature of 80 C. should not be exceeded. The time of reaction is dependent upon the catalyst, temperature and concentration of the oxygen. Furthermore it is highly dependent upon pressure, wherefore it is advisable above all to work under increased pressure, such, for example, as pressures of 5 to 30 atmospheres. When working under a pressure of about 10-20 atmospheres the reaction time is only about I/lO-l/ZO of the time needed when working atv atmospheric pressure. 1

' To avoid losses of solvent, it is necessary/to work at very good 'reflux cooling. The quantities'of solvent nevertheless drawn along by the current of gas can be held back according to various known ways, thus for example by intensive separation or by active carbon filter.

The isolation of the product is done in simplest manner by distilling the solvent off, with ensuring vacuum distillation of the residue. By distillation, the ketoximes are obtained in technically pure form. The yield when the isolation is accomplished in this way amounts to about 90%. Naturally also, other processes of isolation are possible, as for example extractive separation with suitable selective solvents. The yield of oxime is very high and can amount to above 90% Example 1 In a pressure vessel 9 grams of cyclohexylhydroxylamine are mixed with 400 ccm. of cyclohexane and heated to 45 C. To this are added 10 ccm. of a coppernaphthenate catalyst solution in cyclohexane, which contains about 0.2 gram of the metal-ion. In this mixture, a current of air is conducted through at a pressure of 15 atm. with thorough stirring and with reflux cooling for a period of 30-35 minutes. The temperature is kept at 45 C. After the solvent has been distilled ofl? at normal pressure, the residue is distilled in vacuum at 0.15 mm. Hg and at a transition temperature of 8298 C. 7.5 grams of pure cyclohexanonoxime of the melting point 86 C. are obtained, corresponding to a yield of Example 2 In a pressure vessel 11.5 grams of cyclohexylhydroxylamine are dissolved in 400 ccm. of methanol by heating to 40 C. T 0 this solution, 12.8 ccm. of a copper-cobaltoleate catalyst solution are added in methanol, which contains about 0.1 gram of each metal-ion. After introduction of oxygen under a pressure of 20 atm. during 25 minutes at 40 C. with reflux cooling, 7.8 grams of cyclohexanonoxirne are obtained after isolation, corresponding to a yield of 70%.

Example 3 A mixture of 11.5 grams of cyclohexylhydroxylamine V and 400 ccm. of cyclohexane is poured into a pressure vessel. Then 12.8 ccm. of a catalyst solution of cobaltlead-manganese naphthenate in cyclohexane are added, which contains 0.014 gram, 0.17 gram and 0.014 gram of the metal-ions respectively. Through this mixture, a current of air is conducted with reflux cooling at 60 C. and 10 atmospheres pressure for fifteen minutes. After the usual isolation, 10.2 grams of cyclohexanonoxime are obtained with a 90% yield.

3 Example 4 In a pressure vessel 10.5 grams of cyclopen-tylhydroxylamine are mixed with 500 ccm. of benzene and heated to 60 C. After :addition of 1218 cam. of :a solution of copper-mangarrese-vanadiumaoleate 'in benzol. containing about 0.03 gram 'of :each 'metal=ion, air is conducted through at160 Cnand2O atmospherespressure during 20 minutes with refluxcooling. Thereupon, the solvent is separated by evaporation and at good vacuum the residue is distilled. There are obtained 7.9 grams of cyclopentanonoxime of melting point 57-58", corresponding to-a yield of 801%..

ExampZe S In 'a pressure vessel 35 grams of cyclohexylhydnoxylamine are mixed With '315'grams of n-propanol. An amount of cobalt naphthenate is added which contains about 0.035 g. of cobalt ion. 'The mixture is heated to 70 C., and air isipressed into the vessel up to a pressure of 30 atm. At this temperature and pressure an amount of 100 liters'of air is blown through the reaction mixture during '10 minutes. The used air is continuously expanded'throu'gh 'a'valve and a reflux cooler. After this time the propanol is distilled otf at normal pressure and the residue is distilled "in vacuum. '31 grams of a white distillate are obtained which is pure cyclohexanone oxime of a melting point of 89 C.

What we claim is:

A process of producing a :material of the class consisting of cyclopent anonoxime and cyclohexanonoxirne by homogenous'ly catalytically oxidizing the corresponding hydroxylarnine at temperature between 20 C. and 80 C. by means'of oxygen-containing gas-under v1a pres sure of from 5 110.30 atmospheres in asolvent of'the class consisting of methanol, ethanol, propanol, cyclohexane, and benzene, the catalyst being seleetedfromthe class consisting of copper-naphthanate, copper-cobaltoleate, cobalt-lead manganese-naphthanate, coppermanganese-vanadium=oleate, and -cobalt-naphthanate.

References Cited in the file of this patent UNITED STATES PATENTS 2,245,528 Loder June 1.0, 1941 2,472,503 'Minne June .7, 1942 2,578,654 Hearne .Dec..18, 195.1 

